1. Field of the Invention
The present invention relates to spring holding mechanisms for holding springs attached to rotation shafts interconnecting drum beaters and foot pedals in bass drums.
The present application claims priority on Japanese Patent Application No. 2009-1452, the content of which is incorporated herein by reference.
2. Description of the Related Art
Conventionally, foot pedals (or foot boards) interconnected with drum beaters have been used for bass drum performances, wherein players depress foot pedals to pivotally operate drum beaters, which beat the drumheads of bass drums. Foot pedals and drum beaters are interconnected together via rotation shafts, which are interconnected with springs for imparting tensile forces in a radial direction. When players release foot pedals from being depressed, foot pedals and drum beaters are returned to normal positions due to the tensile force of the springs.
Patent Document 1: U.S. Pat. No. 5,365,824
Patent Document 1 discloses a spring adjustment mechanism for holding one end of a spring opposite to another end interconnected to a rotation shaft. Herein, a bolt is connected to one end of the spring and is inserted into a hole formed in a support frame. The bolt is engaged with a pair of nuts that tightly hold the support frame at both sides in an axial direction of the hole, so that the spring is being held by the bolt being fixed in position.
Patent Document 1 discloses that the contact area between the nuts and the support frame is formed in a horizontal plane perpendicular to the axial line of the bolt; hence, nuts easily get loosened so as to weaken the bolt holding the spring during performance. This causes positional deviation or backlash of the bolt, which in turn causes unwanted noise or which varies the spring that forces the foot pedal and drumbeater to return to their original positions, thus impairing the performing ability of a bass drum.